Intelligrated, a manufacturer of material handling systems in Mason, Ohio, uses device networks to control equipment and uses Ethernet to connect that equipment to higher-level systems. "We use device networks in products that have clusters of distributed I/O, for example, along a run of conveyor," Matt Wicks, vice president of systems engineering, explains. "These clusters then are connected to controllers via Ethernet."
Intelligrated uses DeviceNet and B&R Automation's X2X device networks, and sometimes they don't need Ethernet to connect to controllers. "On conveyors where there's a 'head end' unit, we use Ethernet to interface between the device network and the controller," he notes. "For machines such as palletizers, on which devices like drives are clustered together in close physical proximity, the device network is connected directly back to the controller."
Wicks says the device networks are useful in this manner because they are self-contained and hold both communications and power wiring in a single cable. They also can run without switches, and have the physical and electrical robustness to be run on a machine without the need for conduit or cable tray.
"Ethernet is the primary network connectivity method for our machines, robotics and associated material handling systems," he says. "Ethernet enables all controller-level communications to be seamless by connecting HMIs, drives, I/O aggregation points or higher-level software so that they use the same network topology."
For the higher-level networks, Intelligrated uses standard Ethernet, Profinet and sometimes ControlNet.
Mixing the networks doesn't pose a problem. "Knowing how to manage and design this level of networking requires some different skills than traditionally seen in the industrial control, but there are many tools available that allow engineers to appropriately design a successful network," Wicks says.
"Ethernet will continue to be pervasive in industrial controls. "With improved cabling standards, PoE and embedded switch technology integrated into end devices — Ethernet will continue to encroach on the current space occupied by device networks."